DESCRIPTION: Children requiring repeated invasive medical procedures may develop behavioral disturbances despite pharmacological interventions for pain. Behavioral distress disrupts procedures, diminishes the child's quality of life, stresses THE family, and may impact the child's overall psychological adjustment. Children ages three to seven will be studied as they undergo repeated (needle stick) procedures (e.g. venipuncture, infusaport sticks, subcutaneous or intramuscular injections). The effects of three behavioral interventions for supplementing medical management of procedural pain will be compared. Experimental groups will be stratified by baseline behavioral distress, intensity of the medical protocol, age and gender. Behavioral distress and related variables will be measured during a series of five consecutive needle stick procedures of the same type for each child. The Operant intervention includes procedures from the basic research literature on operant and respondent conditioning, which have reduced negative behavioral effects of aversive stimulation consistently and across species. The Interactive Distraction intervention uses salient and novel stimuli to compete with the child's perception of noxious stimuli, and was designed to be highly cost-effective. The third, Usual Care intervention is based on standard nursing care. A group experimental design will compare treatment effects on: (1) behavioral and physiological measures of distress during needle sticks, (2) a standardized measure of overall behavioral adjustment, and (3) professional time required. The Operant intervention should produce the most robust and immediate improvements in procedure-related distress and arousal, but will be more costly. Interactive Distraction should be effective for children with lower levels of behavioral distress, and may prevent the development of severe behavioral distress. The Operant intervention, which emphasizes behavioral momentum, discrimination training and counterconditioning during simulated medical procedures (in addition to distraction) is expected to be more effective for children with severe behavioral distress and evidence of conditioned anxiety at baseline. A multivariate analysis of covariance will examine the value of screening measures of child coping style, developmental status, age and baseline behavioral distress in predicting differential responses to the three interventions. The results may lead to better matching of interventions to children for greater treatment economy.